1. Field of the Invention
The present invention relates to a digital television signal, and more particularly, to a digital television signal for receiving program and system information protocol (PSIP) data, a method of processing the digital television signal, and a digital television receiver. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for resolving errors that occur when a rating region table (RRT) is upgraded constantly (or whenever necessary) and for quickly determining whether the RRT is upgraded.
2. Discussion of the Related Art
A program and system information protocol (PSIP) is defined for parsing messages encoded in specific modes, such as MPEG-2 (moving pictures experts group ; ISO/IEC 13818-1 System), so as to provide diverse information on a particular digital broadcast program. The PSIP basically has the same structure as a PSI of the MPEG system. The PSIP may also be configured of a group of tables having the same object or purpose. Herein, each of the tables may be divided into several sections and then transmitted. Such tables include a virtual channel table (VCT), a system time table (STT), a rating region table (RRT), an extended text table (ETT), a direct channel change table (DCCT) and/or a direct channel change selection code table (DCCSCT), an event information table (EIT), a program map table (PMT), and a master guide table (MGT).
More specifically, the STT provides time information of the broadcast program, and the RRT transmits information on a specific region and an advisory committee for the program rating. The ETT provides additional channel and broadcast program description. The DCCT and the DCCSCT are related with automatic (or direct) change in channels. The EIT provides event information (e.g., title, starting time, etc.) of a virtual channel. Finally, the MGT is for managing versions and packet identifier (PID) of each of the above-mentioned tables. Particularly, among the above-mentioned tables, the RRT is configured with information of a program rating system existing in a specific region. The RRT is a standard table for a ‘Content_Advisory_Descriptor’, which indicates event schedules and program ratings existing in the EIT or the PMT, wherein information of each event is included.
However, in the related art digital broadcasting, a method for controlling the tables related to program rating information of the PSIP, a digital broadcast signal including the data structure of the above-mentioned tables, and a digital television receiver processing the digital broadcast signal have the following disadvantages. When a program rating standard is changed, tables related with the updated program rating information, such as the RRT, must be transmitted. A program rating standard that could be updated may be, for example, found in Downloadable U.S. Region Rating System White Paper published by Consumer Electronics Association (CEA) White Paper in Dec. 15, 2005. And, the digital television receiver should be capable of determining whether the program rating information has been changed. Yet, in the related art, the number of bits allocated for identifying the version of the tables related with the program rating information, such as the RRT, is extremely limited. Thus, the digital television receiver may not be able to discriminate between an old version of the RRT and a newer version of RRT.